1. Field of the Invention
The present invention relates to a measuring apparatus; and more particularly, to an apparatus for measuring the dimensions of surfaces extending at different helical angles. Although the present invention is suitable for measuring dimensions of many different helical surfaces, it is particularly advantageous for measuring the land of endmills having a helical cutting surface, and will be specifically described in connection therewith.
2. Discussion of the Related Art
An endmill is similar to a drill bit, both are instruments used to cut or bore holes. The difference being a drill bit utilizes its point to cut; whereas an endmill utilizes side surfaces or lands to cut.
The traditional approach to measuring the land of an endmill is to place the endmill into clay or a block of wood and view the primary land with a microscope. There are a number of disadvantages associated with the traditional approach of measuring land width. The primary problem is obtaining accurate measurements. The placement of an endmill into clay or a block of wood inherently gives rise to unwanted movement of the endmill. Specifically, the block of wood becomes worn through use and increases the hole size associated with any given endmill diameter placed into the block. In addition, in order for an accurate measurement to be taken, the helical surface to be measured must be completely parallel to the platform of the microscope. To accurately place the endmill in such a position by using the traditional approach is nearly impossible. These problems are further compounded by the fact that the measuring procedure is required to be repeated throughout the work life of the endmill.
Another difficult obstacle to overcome, which is practically impossible using the traditional approach, is locating the place on the endmill which was initially measured in order to repeat the measuring procedure after its use.
Finally, the traditional approach is extraordinarily inefficient when considering the measuring procedure must take place on numerous endmills with various diameters and helical angles.